*3.1. Structure and Transition of PLE Land Use*

The Yellow River basin was mainly dominated by ecological space, with the percentage of ecological space being 55.73%, 55.97%, and 55.99% in 2000, 2010, and 2018, respectively, showing an increasing trend (Figure 3). The northwestern and southern parts of the study area were relatively less densely populated and had a lower level of urbanization and were therefore dominated by ecological space. The percentage of production space was 40.79%, 39.38%, and 38.91% in 2000, 2010, and 2018, respectively, showing a decreasing trend. Production space was mainly located in the eastern coastal areas of the study area, which have better water and heat conditions and are also conducive to crop growth. The region is economically developed, highly urbanized, with a high level of human activity and is a major industrial center and food producer.. The percentage of living space increased from 3.48% in 2000 to 5.10% in 2018. Spatially, living space was mainly distributed around the

main cities in the study area, showing a tendency to spread outwards. The chord diagram suggests the scale of transfer of different land uses. The direction shown by the arrow represents the direction of transfer of the land, and the width of the arrow represents the proportion of the area transferred (Figure 3). According to the area conversion of PLES from 2000 to 2018, the largest area of production land was converted outwards, with a total of 35,300 km2, of which 10,800 km2 was converted to living land and 24,500 km2 was converted to ecological land. The smallest area of living land was converted outwards, with a total of 3720 km2, of which 3280 km2 was converted to production land and 433 km2 to ecological land. Ecological land converted mainly into productive land was 21,500 km2, while converted into living land was 1940 km2.

**Figure 3.** Structure and transition of production-living-ecological space in the Yellow River Basin from 2000 to 2018.
